Modulation of cross-hierarchy propagating waves across sleep stages

Motivation: Endogenous brain activity plays a pivotal role during sleep. Previous research suggested that endogenous brain activity during wakefulness can take the form of infra-slow waves propagating along the cortical hierarchical gradient. But it remains unclear how these infra-slow waves modulate across sleep stages. Goal(s): To elucidate sleep stage dependent changes in the cross-hierarchy propagations. Approach: We measured and analyzed overnight fMRI/EEG data. Results: The cross-hierarchy propagating waves modulate systematically across sleep stages. REM sleep features more frequent propagations from sensory/motor regions to higher-order brain networks, which are associated with eye movements and characterized by phase shifts in the thalamus, pons, and visual cortex. Impact: The findings reveal a highly structured nature of endogenous brain dynamics during REM sleep and their potential link to known REM features of electrophysiological PGO waves and eye movements.